• School Mathematics
• /
• v.10 no.3
• /
• pp.443-461
• /
• 2008

The purpose of this study was to provide teachers with suggestions on how to teach the unit of finding the area of plane figure by analyzing students' different solution methods. The solution methods were analyzed according to how the original area of the given figure was kept: partition, transformation, and elimination. The partition method was most used. With regard to transformation, students seemed to find it easy to use the area of rectangle. With regard to elimination, students were successful using elimination to find the area of a given figure but had difficulty in producing a formula from the method. The teacher played a key role to encourage students to employ different solution methods, and gave them opportunities to compare and contrast various methods. A cautionary note is that, with too much emphasis on 'variety', the mathematical efficiency may be lost in the process. It suggests that a teacher should be careful to establish appropriate sociomathe- matical norms with students in order that they can make their own judgment on which solution method is mathematically worth and efficient.

• Applied Chemistry for Engineering
• /
• v.17 no.6
• /
• pp.633-637
• /
• 2006

In this study, the efficient large-scale synthetic route for itraconazole, triazole antifungal agent, was developed. The original synthetic route for medicinal chemistry reported by Janssen Pharmaceutica was linear (14 linear steps) starting from 2,4-dichloroacetophenone with the total yield of 1.4%, and potential hazardous materials such as methanesulfonyl chloride ($CH_{3}SO_{2}Cl$), hydrogen gas, and sodium hydride (NaH) were used. Furthermore, the expensive 1-acetyl-4-(4-hydroxyphenyl)piperazine and palladium were used in this medicinal chemistry route, thus the manufacturing cost would be practically high. In order to improve the commercial route, we developed the process of 12 step convergent synthesis combining two intermediates which are roughly halves of itraconazole with the total yield of 12.0%, and hazardous materials and expensive reagents were excluded in this process, thus the manufacturing cost could be cut down to a great extent.

• Journal of Internet Computing and Services
• /
• v.10 no.5
• /
• pp.27-32
• /
• 2009

Colored thread algorithm, suggested to be used for the label switching network, needs to be modified for the packet switching network. In this paper, it is recommended to add a merged state, besides the 3 states - null, colored and transparent - which are resulted from the behaviors of extend, rewind, stall, withdraw and merge events. The original colored thread algorithm is designed to generate a new thread and extend it to the downstream direction with unknown hop count when the thread has revisited the node that was visited. It also suggested rewinding the thread to the downstream direction by the source node, instead of rewinding it upstream direction by the revisited node. If a node received multiple threads which had a same forward equivalent class, then it checks first whether the hop counts are ascending or not. If it is in ascending order, then threads are merged. Otherwise the later thread is stalled until the former thread's color is to be changed to transparent or it is removed. This idea removes the effort of generating a new thread with unknown hop count.

• Journal of the Institute of Convergence Signal Processing
• /
• v.1 no.1
• /
• pp.23-31
• /
• 2000

Iterative curve evolution techniques are powerful methods for image segmentation. Classical methods proposed curve evolutions which guarantee close contours at convergence and, combined with the level set method, they easily handled curve topology changes. In this paper, we present a new geometric active contour model based on level set methods introduced by Osher & Sethian for detection of object boundaries or shape and we adopt anisotropic diffusion filtering method for removing noise from original image. Classical methods allow only one-way curve evolutions : shrinking or expanding of the curve. Thus, the initial curve must encircle all the objects to be segmented or several curves must be used, each one totally inside one object. But our method allows a two-way curve evolution : parts of the curve evolve in the outward direction while others evolve in the inward direction. It offers much more freedom in the initial curve position than with a classical geodesic search method. Our algorithm performs accurate and precise segmentations from noisy images with complex objects(jncluding sharp angles, deep concavities or holes), Besides it easily handled curve topology changes. In order to minimize the processing time, we use the narrow band method which allows us to perform calculations in the neighborhood of the contour and not in the whole image.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2004.04a
• /
• pp.55-60
• /
• 2004

The paper describes measurement techniques for an acoustic transfer characteristic of ship's bridge stimulated by a whistle sound. The response sounds, according to the opening-shutting conditions of bridge doors for T／S ‘SAENURI’, are measured by B＆K 2260D equipment, and then extracted the frequency responses by B＆K 7830 software. To evaluate the measured transfer characteristic, the 128th order FIR (Finite Impulse Response) filters, containing the frequency characteristic, are constructed based on the frequency sampling-based design method. Using evaluation indexes with six scales, psychological assessments by five subjects are carried out with test sounds which are convolved source sound and FIR filters. As results of tests, the test sounds gives A／sub s／=3.3∼4.7 which means the psychological sense of 'it is almost similar sound as original ones in a real world', and thus it is cleary seen tint the proposed method can be suit for the measurement of an acoustic transfer characteristic of ship's bridg.

• Journal of the Korean Society of Environmental Restoration Technology
• /
• v.3 no.4
• /
• pp.84-90
• /
• 2000

The objective of this study was to introduce the current status and development strategy for an environmental restoration of stream side in Japan, and to consider a methodology which could be effectively applied for the environmental restoration of stream side in Korea. 1. In order to change the recent direction of the forest conservation and erosion control projects which are focused on the restoration of stream side ecology, we have to quit the past erosion control policy such as water control purpose, and establish new plans regarding on the forest conservation and erosion control which is considered the regional environmental restoration of watershed. 2. When we restore stream side and river side ecosystem, we should establish restoration plans which can keep the original nature of stream and river. 3. The forest conservation and erosion control construction projects for the restoration of stream and river ecosystem should be planned for the perfect restoration of their ecosystem by way of sustainable maintenance and management. 4. The restoration direction of stream and river ecosystem needs to be planned to restore the diversity of small geographies such as waterway, shoal and puddles rather than flattening of stream bed. 5. The main principle in the restoration of stream and river ecosystem is to accomplish forest conservation and erosion control construction projects which can conserve the existing stream and river ecosystem.

• Journal of Embryo Transfer
• /
• v.25 no.4
• /
• pp.207-213
• /
• 2010

Thousands of new chemicals have been introduced to environment during last decades. Many of them and common consumer products have been shown to be the endocrine disrupting chemicals. One such chemical group is the phthalates, used in soft poly vinyl chloride (PVC) material and in a huge number of consumer products. The prevalence of these modem chemicals have a remarkable increase. Approximately 3.5 million tons of the main phthalate, di-(2-ethylhexyl) phthalate (DEHP), are produced annually worldwide and indeed, DEHP is considered a ubiquitous environmental contaminant. It has been demonstrated that high doses of phthalate can adversely affect adult and developing animals. In this review, we critically discuss the conclusions of recently original research papers and provide an overview of studies on reproductive disrupting effects of phthalates. In addition, we review the reproductive toxicity data of phthalates in some in vitro research and in both male and female reproductive systems in experimental and domestic animals. Finally, we point out some critical issues that should be addressed in order to clarify the implication of phthalates for human reproduction.

• Journal of Korean Society for Geospatial Information Science
• /
• v.20 no.3
• /
• pp.41-48
• /
• 2012

Using multi-sensor or multi-temporal high resolution satellite images together is essential for efficient applications in remote sensing area. The purpose of this paper is to estimate geometric difference of translations between high-resolution optical and SAR images automatically. The geometric and radiometric pre-processing steps were fulfilled to calculate the similarity between optical and SAR images by using Mutual Information method. The coarsest-level pyramid images of each sensor constructed by gaussian pyramid method were generated to estimate the initial translation difference of the x, y directions for calculation efficiency. The precise geometric difference of translations was able to be estimated by applying this method from coarsest-level pyramid image to original image in order. Yet even when considered only translation between optical and SAR images, the proposed method showed RMSE lower than 5m in all study sites.

• International Journal of Human Ecology
• /
• v.9 no.2
• /
• pp.107-116
• /
• 2008

A new movement in forming community villages for better living standards is becoming popular. In order to sustain a proper community, it is essential to design proper community programs and facilities, which can encourage the proactive participation of residents. In this study, detailed aspects of the Mindlre (Dandelion) community (including formation process and management of the village) are investigated. The Mindlre community is a successful community village in Korea concerned with residents' participation and community activities. The community is located in Sancheong, Gyungsangnamdo province in Korea. The study methods are references, field trips, and interviews with residents. Six areas were surveyed and investigated: the physical environment of the Mindlre community and eco-friendly elements, respondents' background and the motivation to join, residents composition, residents' participation in the formation process of the community, self-management systems and common activities, and residents's life satisfaction. The mindlre Community was founded on Christian religions faith. The primary idea of this village was building a new hope for rural areas without discrimination. The size of the village was expanded with housing for teachers and students who were linked with the Mindlre School (substitution school). When the community was founded, existing shapes of the village were preserved. The village was physically renovated based on the original environment, in addition nature friendly materials and methods were used. The residents were proactively involved in the community through regular meetings, self-regulation, and community worship. Although the survey results should that most residents were highly satisfied with living standards, there seemed to be no clear division between community facilities and private houses. A systematic and detailed space planning technique was required. In addition, various community facilities are required due to the expansion of the community.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.26 no.11C
• /
• pp.113-122
• /
• 2001

Several guidelines can be developed for a satellite-based ATM switch. One of the most important of these is that the switch must provide a requirement for CLRs on the order of 10-10 to meet the QoS of high- performance traffic and avoid costly retransmissions. In this paper, the proposed approach shows not only the better traffic performance but also requires the little switching elements and buffers compared with original Knockout switch and other scheduling algorithm. As a result, the complexity becomes reduced. Simulation results indicate that proposed approach shows excellent cell loss ratio compared with existing switch architecture. Also, iii performance can be approached to the cell loss ratio, which is requirement for the satellite system, as window size increases. An(1 it shows thats low complexity is induced. Therefore, the proposed approach is appropriate for satellite on-board ATM switch architecture.